WO2007086352A1

WO2007086352A1 - Imaging element and camera module

Info

Publication number: WO2007086352A1
Application number: PCT/JP2007/050936
Authority: WO
Inventors: Katsuhide Setoguchi
Original assignee: Kyocera Corporation
Priority date: 2006-01-25
Filing date: 2007-01-23
Publication date: 2007-08-02
Also published as: US20090008532A1; JPWO2007086352A1; JP4907557B2; US8119965B2; WO2007086352A8

Abstract

Provided is an imaging element capable of performing imaging with an appropriate dynamic range even if the bright-dark difference in the imaging range is large. An imaging element (1) includes: a substrate (2); a plurality of first photo diodes (5) arranged to correspond to a plurality of pixels (3) on the substrate (2) to receive light coming to a first main surface (S1) and generate an electric charge in accordance with the received light quantity; and a plurality of second photo diodes (6) arranged to correspond to a plurality of pixels (3) on the rear side of the first photo diodes (5) to receive light which has come to the first main surface (S1) and has passed through at least one of the plurality of first photo diodes (5) and the substrate (2) and generate an electric charge in accordance with the received light quantity. An electric signal based on the electric charge generated by the plurality of first photo diodes (5) is added by an electric signal based on the electric charge generated by the second photo diodes (6) of the same pixel.

Description

Specification

Image sensor and camera module

Technical field

The present invention relates to an image sensor such as a CMOS image sensor and a camera module including the image sensor. Background art

[0002] In a solid-state imaging device such as a CMOS image sensor, a charge corresponding to incident light is generated by a light receiving element, and an image to be imaged is acquired by sequentially reading out charges accumulated in each light receiving element. It is known that when the amount of light received increases, the charge in the light receiving element is saturated, and so-called whiteout occurs.

[0003] In Patent Document 1, two photodiodes are provided in each pixel, and the charge (potential) of one photodiode is reduced by the charge (potential) of the other photodiode in the peripheral pixel, thereby saturating the charge. A technique for preventing the above is disclosed. Patent Document 1 also discloses a technique in which the other photodiode is arranged directly below one photodiode.

[0004] Although not related to a technique for preventing saturation in a light receiving element, a technique is also known in which a photodiode is provided on one main surface of a substrate and a photodiode is provided on the other main surface (Patent Document 2, 3).

Patent Document 1: Japanese Unexamined Patent Publication No. 2003-169252

Patent Document 2: JP-A-5-243548

Patent Document 3: Japanese Patent Application Laid-Open No. 2004-103964

Disclosure of the invention

Problems to be solved by the invention

[0005] With the technique of Patent Document 1, the captured image is different from the actual luminance distribution, although the power of lowering the relative charge of the pixels having a larger average light amount in the periphery is relatively low. That is, in the technique of Patent Document 1, the luminance distribution of the obtained image is smoothed more than the actual luminance distribution. Therefore, for example, it is not suitable for application to a technology in which a difference in brightness is important for detection accuracy, such as an in-vehicle camera module that detects a white line on a road based on a captured image, It is desirable to prevent deterioration of image quality due to saturation of the light receiving part while reflecting the actual luminance distribution.

[0006] That is, it is desired to provide an image sensor that can capture an image with an appropriate dynamic range and a camera module that includes the image sensor even when the difference in brightness within the imaging range is large.

Means for solving the problem

The imaging device of the present invention is a light receiving element provided for each of the substrate and the pixels obtained by dividing the substrate into a plurality of pixels, and is provided on the substrate and receives light incident on one main surface of the substrate. A first light receiving element that generates an electric charge according to the amount of light received, and a light receiving element provided for each pixel, provided at a position behind the first light receiving element and incident on the one main surface. A second light receiving element that receives light transmitted through at least one of the first light receiving element and the substrate and generates a charge corresponding to the amount of light received, and a signal of an electric signal based on the charge generated in the first light receiving element An increase unit configured to increase the level so that the amount of increase increases as the signal level of the electric signal based on the charge generated in the second light receiving element of the same pixel increases. .

Preferably, the first light receiving element is provided on the one main surface, and the second light receiving element is provided on the other main surface of the substrate.

[0009] Preferably, a second substrate is provided opposite to the other main surface of the substrate, and the second light receiving element is provided on the second substrate.

[0010] Preferably, the first light receiving element is provided on the one main surface of the substrate, and the second light receiving element is a main surface of the second substrate facing the other main surface of the substrate. Is provided in

[0011] Preferably, the first light receiving element is provided on the other main surface of the substrate, and the second light receiving element is a main surface of the second substrate that faces the other main surface of the substrate. It is provided on the surface.

[0012] Preferably, at least a part of the increase unit and the increase control unit that controls the operation of the increase unit is provided on the second substrate.

[0013] Preferably, the increase unit generates an electric signal based on an electric charge generated in the first light receiving element. Then, an electric signal based on the electric charge generated in the second light receiving element of the same pixel is added.

[0014] Preferably, the increase unit includes an amplifying element that amplifies an electric signal based on the electric charge generated in the first light receiving element, and the amplifying element uses the electric charge generated in the second light receiving element. The higher the signal level of the electric signal based, the higher the amplification factor when amplifying the electric signal based on the electric charge generated in the first light receiving element of the same pixel.

[0015] Preferably, a third light receiving element disposed on the same plane as a surface on which a plurality of the second light receiving elements are arranged, and a light shielding member that blocks light from the one main surface side toward the third light receiving element. A signal level force of an electric signal based on the electric charge generated in the second light receiving element, and the increase unit subtracts a signal level of the electric signal based on the electric charge generated in the third light receiving element. The signal level of the electric signal based on the charge generated in the second light receiving element is corrected, and the signal level of the electric signal based on the charge generated in the first light receiving element is corrected based on the corrected signal level. increase.

[0016] Preferably, based on at least one of an electric signal based on the electric charge generated in the first light receiving element and an electric signal based on the electric charge generated in the second light receiving element, and thereafter A saturation level control unit configured to control the saturation level of the first light receiving element so that the degree of charge saturation in the one light receiving element is within a predetermined range is provided.

[0017] Preferably, the pixels on the outer peripheral side of the pixel array region are arranged such that the second light receiving elements are shifted from the first light receiving element of the same pixel toward the outer peripheral side of the pixel array region.

[0018] Preferably, the second light receiving element protrudes to the outer peripheral side of the pixel arrangement region with respect to the first light receiving element having a light receiving area larger than that of the first light receiving element.

[0019] A camera module of the present invention includes a lens, an image sensor on which light from the lens forms an image, and a signal processing unit configured to process an electrical signal output from the image sensor, The image sensor is a light receiving element provided for each pixel obtained by dividing the substrate and the substrate into a plurality of pixels. The image receiving element is provided on the substrate and receives light incident on one main surface of the substrate. A first light-receiving element that generates a corresponding charge, and a light-receiving element provided for each pixel, provided at a position behind the first light-receiving element, and incident on the one main surface and the first light-receiving element And receiving light transmitted through at least one of the substrates, depending on the amount of light received And the signal processing unit generates a signal level of an electrical signal based on the charge generated in the first light receiving element in the second light receiving element of the same pixel. It is configured to increase the amount of increase so that the amount of increase increases as the signal level of the electric signal based on the charge increases.

[0020] Preferably, the second light receiving element is arranged so as to be shifted in a direction away from the optical axis with respect to the first light receiving element of the same pixel, as the pixel is located away from the optical axis force of the lens. Yes.

The invention's effect

[0021] According to the present invention, it is possible to capture an image with an appropriate dynamic range even when the brightness difference within the imaging range is large.

Brief Description of Drawings

FIG. 1 is a cross-sectional view schematically showing an imaging element according to a first embodiment of the present invention.

FIG. 2 is a diagram for explaining a basic concept of signal processing in the image sensor of FIG.

FIG. 3 shows a circuit configuration of a pixel of the image sensor in FIG.

4 is a diagram for explaining the state of saturation level control in the image sensor of FIG. 1.

FIG. 5 is a diagram showing a circuit configuration of a pixel of an image sensor according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a circuit configuration of a pixel of an image sensor according to a third embodiment of the present invention.

FIG. 7 is a diagram showing a circuit configuration of a pixel of an image sensor according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view schematically showing an image sensor according to a fifth embodiment of the present invention.

FIG. 9 is a plan view schematically showing the image sensor of FIG.

10 is a diagram showing a circuit configuration of a pixel of the image sensor in FIG.

FIG. 11 is a cross-sectional view and a plan view schematically showing an image sensor according to a sixth embodiment of the present invention.

FIG. 12 is a block diagram showing a basic configuration of a camera module according to a seventh embodiment of the present invention.

FIG. 13 is a block diagram showing the basic configuration of a camera module according to an eighth embodiment of the present invention.

FIG. 14 is a cross-sectional view schematically showing an image sensor of a ninth embodiment of the present invention.

FIG. 15 is a cross-sectional view schematically showing an image sensor according to a tenth embodiment of the present invention.

FIG. 16 is a cross-sectional view schematically showing an image sensor according to an eleventh embodiment of the present invention.

Explanation of symbols [0023] 2 ... substrate, 3 ... pixel, 5 ... first light receiving element, 6 ... second light receiving element, SN ... node (increasing part), S1 main surface, S2 "-other main surface.

BEST MODE FOR CARRYING OUT THE INVENTION

[0024] (First embodiment)

FIG. 1 is a cross-sectional view schematically showing the image sensor 1 according to the first embodiment of the present invention. The image pickup device 1 is configured by, for example, a MOS type image pickup device, and includes a substrate 2 and a first photodiode (first light receiving device, photoelectric detector) provided on the first main surface (one main surface) S 1 of the substrate 2. Conversion element) 5 and a second photodiode (second light receiving element, photoelectric conversion element) 6 provided on the second main surface (other main surface) S2 on the back side.

[0025] The first photodiode 5 and the second photodiode 6 are respectively provided in a plurality of pixels 3 obtained by dividing the substrate 2 into hundreds to thousands of pixels in the X direction (backward direction on the paper surface) and the Y direction (left and right direction on the paper surface). One is provided, and a plurality of arrays are arranged in the X and Y directions. The first photodiode 5 and the second photodiode 6 are arranged so as to face each other with the substrate 2 interposed therebetween.

[0026] The first photodiode 5 receives light incident on the first main surface S1, and photoelectrically converts the received light to generate a charge corresponding to the amount of light received. The second photodiode 6 is arranged at a position closer to the second main surface S2 side of the substrate 2 than the first photodiode 5 (behind the first photodiode 5), and is incident on the first main surface S1. Light passing through at least one of the first photodiode 5 and the substrate 2 is received, and the received light is photoelectrically converted to generate a charge corresponding to the amount of light received. Each pixel has a first electrode 9 for detecting a signal based on the charge generated in the first photodiode 5, a second electrode 10 for detecting a signal based on the charge generated in the second photodiode 6, and the like. Is provided.

[0027] The configuration of the substrate 2, the first photodiode 5, and the first electrode 9 may be a known appropriate configuration. Further, the second photodiode 6 and the second electrode 10 are also arranged on the second main surface S2 opposite to the first main surface S1, except for the first photodiode 5 and the first electrode 9. A similar configuration may be used. For example, the substrate 2 is a P-type semiconductor element substrate made of silicon (Si) as a main material, and the first photodiode 5 and the second photodiode 6 are formed by PN junctions and are formed on the force sword side ( N-type semiconductor side) is exposed from substrate 2 and anode side (P-type semiconductor) The body side is buried in the substrate 2. The second photodiode 6 is formed, for example, in the same material and shape as the first photodiode 5, and is manufactured and mounted in the same process as the manufacturing of the first photodiode 5 and the mounting on the substrate 2. .

FIG. 2 is a diagram for explaining the basic concept of signal processing in the image sensor 1, FIG. 2A shows the output signal of the first photodiode 5, FIG. 2B shows the output signal of the second photodiode 6, FIG. 2C shows an output signal when the output signal of the first photodiode 5 is corrected based on the output signal of the second photodiode 6. In each figure, the horizontal axis indicates the position of the image sensor 1 in the X direction (or Y direction), and the vertical axis indicates the amount of light received by the image sensor 1 and the signal level corresponding to the amount of received light (or the signal level). (Increased) is shown in a 1: 1 ratio.

In FIG. 2A, a solid line L1 shows an example of a light amount distribution of light incident on the first main surface S1 of the image sensor 1 when a predetermined imaging target is imaged. In this example, the first main surface The amount of light at the center of S1 is large and the light intensity is decreasing at both ends. The solid line L2 is connected to the first photodiode 5! The amount of light that saturates the charge and the signal level of the electrical signal corresponding to the amount of light, that is, the saturation level, indicate the signal level of the output signal of the first photodiode 5.

[0030] The amount of light incident on the first major surface S1 exceeds the saturation level in the range of xl to x2. For this reason, the signal level of the electric signal of the first photodiode 5 becomes flat at the level of the saturation level in the range of xl to x2, and xl to x2 with the electric signal of the first photodiode 5 alone. The light quantity distribution in the range cannot be specified.

On the other hand, as shown in FIG. 2B, the light (solid line L1) incident on the first main surface S1 is absorbed by the first photodiode 5 and the substrate 2 by the light quantity Q1, and out of the light quantity indicated by the solid line L1. Only the amount of light above the solid line L4 reaches the second photodiode 6, and is photoelectrically converted by the second photodiode 6 as indicated by the dotted line L6. Here, the range χΐ to χ2 ′ where the light incident on the first main surface S1 reaches the second photodiode 6 is at least partially overlapped with the range of xl to x2.

Therefore, the signal level of the electrical signal of the first photodiode 5 indicated by the dotted line L3 in FIG. 2B is corrected by the signal level of the electrical signal of the second photodiode 6 indicated by the dotted line L6 in FIG. Thus, as shown in FIG. 2C, an electric signal distribution (dotted line L7) appropriately reflecting the light quantity distribution (solid line L1) of the light incident on the first main surface S1 can be obtained.

[0033] The correction method is appropriate. For example, the signal level of the electrical signal of the first photodiode 5 indicated by a dotted line L3 in FIG. 2A and the signal of the electrical signal of the second photodiode 6 indicated by a dotted line L6 in FIG. By adding the level, the electric signal distribution indicated by the dotted line L7 in FIG. 2C can be obtained.

[0034] Further, for example, the distribution of amplification factors when the signal of the first photodiode 5 indicated by the dotted line L3 in Fig. 2A is amplified according to the distribution of the signal level of the second photodiode 6 indicated by the dotted line L6 in Fig. 2B. By changing, the electric signal distribution indicated by the dotted line L7 in FIG. 2C can be obtained. That is, the amplification factor is a constant value in the range of xO to xl (xl ') and χ2 (χ2';) to χ3, and the amplification factor in the range of xl (x;) to χ2 (χ2 '). More specifically, when the signal level of the electric signal of the second photodiode 6 is higher, the higher the gain is, the higher the gain becomes, so that the electric signal indicated by the dotted line L7 in FIG. Can be obtained.

FIG. 3 is a diagram showing a connection relationship between the circuit configuration of the pixel 3 of the image sensor 1 and the vertical drive circuit 20 that controls the readout timing of the pixel 3.

The circuit configuration related to the first photodiode 5 may be a known appropriate configuration. For example, each pixel 3 has a reset transistor 11 that switches the storage node SN to a connection state to the power supply line 17 in the floating state, charges the storage node SN with the power supply voltage VAA, and resets the accumulated charge amount. The first transfer transistor 12 for transferring the charge (usually an electron or a hole) generated in the first photodiode 5 to the storage node SN that has been in a floating state after reset, and the drain connected to the power line 17 And an amplifier transistor 13 that amplifies a pixel signal corresponding to the stored charge transferred to the storage node SN and outputs the amplified signal to the vertical signal line 14.

The reset transistor 11 has a drain connected to the power supply line 17, a source connected to the storage node SN, and a gate connected to the first control line 15 that controls voltage application. The first transfer transistor 12 has a drain connected to the storage node SN, a source connected to a semiconductor impurity region (not shown) that serves as a force sword of the first photodiode 5, and a gate connected to a voltage. Is connected to a second control line 16 for controlling the application of. The amplifier transistor 13 has a drain connected to the power supply line 17, a source connected to the vertical signal line 14, and a gate connected to the storage node SN.

A vertical drive circuit 20 that supplies various voltages to each of the first control line 15 and the second control line 16 is provided around the pixel portion. In addition, a horizontal drive circuit 22 for processing the pixel signal read out to the vertical signal line 14 to convert it into a time-series signal for noise removal or reference level determination (clamping), for example, and reading it out is provided around the pixel portion. Is provided. Further, an operation control circuit (saturation level control unit) 23 for controlling these vertical or horizontal drive circuits is also provided in the image sensor 1.

The pixel 3 further has the following configuration for adding the electrical signal of the second photodiode 6 to the electrical signal of the first photodiode 5.

That is, the pixel 3 includes a second transfer transistor 25 that transfers the charge generated in the second photodiode 6 to the storage node SN that is again in a floating state after reset. The second transfer transistor 25 has a drain connected to the storage node SN, a source connected to a semiconductor impurity region (not shown) that serves as a force sword of the second photodiode 6, and a gate that controls the application of voltage. Connected to control line 16.

The operation of the image sensor 1 having the above configuration will be described.

[0042] In the pixel 3 of the image sensor 1, the reset transistor 11 is turned on and the power supply voltage VAA is applied to the storage node SN, whereby the charge accumulated in the storage node SN is discharged, and each pixel is reset. Is called. Thereafter, the reset transistor 11 is turned off.

[0043] Photoelectric conversion is performed in the first photodiode 5 and the second photodiode 6 with the first transfer transistor 12 and the second transfer transistor 25 turned off, and the first photodiode 5 and the second photodiode 6 Charge is accumulated.

[0044] When a voltage is applied to the second control line 16, the first transfer transistor 12 and the second transfer transistor 25 are turned on simultaneously, and the charges accumulated in the first photodiode 5 and the second photodiode 6 are turned on. (Electrical signals) merge at the storage node SN, and voltage fluctuations occur according to the merged charges.

Therefore, the signal level of the electric signal based on the electric charge generated in the first photodiode 5 is The increase amount increases as the signal level of the electric signal based on the charge generated in the second photodiode 6 of the same pixel increases. The storage node SN has a signal level of an electric signal based on electric charges generated in the plurality of second light receiving elements of the same pixel as a signal level of electric signals based on electric charges generated in the plurality of first light receiving elements. It functions as an increasing part that adds.

The voltage fluctuation generated at the storage node SN is amplified by the amplifier transistor 13 and output to the vertical signal line 14, and the electric signal output to the plurality of vertical signal lines 14 is sequentially output by the horizontal drive circuit 22. . As a result, an output signal (voltage Vpix) of each pixel 3 is obtained.

[0047] In the image sensor 1, the above-described operation in each pixel is repeated for each frame. The operation control circuit of the imaging element 1 is based on at least one of an electric signal based on the electric charge generated in the first photodiode 5 and an electric signal based on the electric charge generated in the second photodiode 6 in one frame. In the next frame, the saturation level of the first photodiode is controlled so that the degree of charge saturation in the plurality of first photodiodes falls within a predetermined range.

FIG. 4 is a diagram for explaining the state of saturation level control in the image sensor 1, in which the horizontal axis indicates the number of frames (time), and the vertical axis indicates the amount of light. Legend Ml indicates the incident light amount of pixel 3 having the maximum incident light amount among the plurality of pixels 3 in each frame, and legend M2 indicates the light amount (saturation level) at which charge is saturated in pixel 3. In the following, a case where control is performed so as to eliminate saturated pixels will be described as an example.

[0049] In frame f 1! /, The incident light intensity falls below the saturation level! /. For frame f 2, the incident light intensity exceeds the saturation level. Therefore, the operation control circuit 23 raises the saturation level in the next frame f 3 relative to the incident light amount. Note that the pixel 3 having the maximum incident light amount and the incident light amount are specified from the output signal (voltage Vpix) corresponding to each pixel output from the horizontal drive circuit 22. The amount of increase in the saturation level is appropriately set according to the light amount dQ2, for example, an amount proportional to the light amount dQ2 of the difference between the incident light amount and the saturation level. The relative increase in the saturation level is performed by shortening the accumulation time and decreasing the amount of photoelectric conversion, or by increasing the power supply voltage VAA applied to the power supply line 17. [0050] In frame f3, the increase in the saturation level does not sufficiently follow the increase in the incident light amount, and the incident light amount still exceeds the saturation level. In the next frame f4, the saturation level exceeds the amount of incident light. The operation control circuit 23 lowers the saturation level when the saturation level becomes too large with respect to the incident light quantity.

[0051] According to the above embodiment, the first photodiode 5 and the substrate 2 are arranged at a position closer to the second main surface S2 than the first photodiode 5, and enter the first main surface S1. A second photodiode 6 that receives light transmitted through at least one and generates a charge corresponding to the amount of light received is provided, and the signal level of the electrical signal based on the charge generated in the first photodiode 5 is set to the second level of the same pixel. Since the amount of increase increases as the signal level of the electrical signal based on the charge generated in the photodiode 6 increases, even if the contrast in the imaging range is large, imaging can be performed with an appropriate dynamic range.

That is, a certain amount of light incident on the first main surface S 1 is absorbed by at least one of the first photodiode 5 and the substrate 2, and the rest reaches the second photodiode 6. Therefore, even in the region where the charge is saturated in the first photodiode 5 and the signal level distribution of the electric signal becomes flat, the second photodiode 6 has a signal corresponding to the light intensity distribution. An electrical signal is output with a level distribution. Then, by increasing the signal level distribution of the signal of the first photodiode 5 by an increase amount corresponding to the signal level distribution, the actual luminance distribution is reflected, and deterioration of the image quality due to saturation of the light receiving unit is prevented. be able to.

[0053] Since the second photodiode 6 is arranged on the second main surface S2 of the substrate 2, compared to the case where the second photodiode 6 is embedded inside the substrate 2, the second photodiode 6 is directed to the substrate 2. Is easy to mount, and the leakage current from the first photodiode 5 prevents the noise from entering the second photodiode 6.

[0054] By adding the electrical signal of the second photodiode 6 to the electrical signal of the first photodiode 5, the signal level of the electrical signal of the first photodiode 6 is increased, so the configuration is simple. is there.

[0055] When the saturation level of the first photodiode 5 is controlled, a control delay as shown in frames f2 and f3 in FIG. 4 occurs. Conventionally, whiteout occurs in frames f2 and f3. It was. However, the second photodiode 6 receives the light amount dQ2 and the light amount dQ3 that are the difference between the actual incident light amount caused by the control delay and the saturation level of the first photodiode 5, and outputs an electrical signal corresponding to the light amount Since the electric signal of the first photodiode 6 is increased according to the output of the electric signal, whiteout can be prevented. In other words, it is possible to capture an image with an appropriate dynamic range when the light-dark difference changes rapidly. Therefore, for example, even when a sharp contrast difference occurs in the imaging range of the in-vehicle camera when the automobile enters or exits the tunnel, it is possible to detect a white line by imaging with an appropriate dynamic range.

[0056] Further, conventionally, in the frames f2 and f3, the light quantity dQ2 and the light quantity dQ3 that are the difference between the actual incident light quantity caused by the control delay and the saturation level of the first photodiode 5 are specified. However, it was difficult to properly determine the control level of the saturation level in the next frames, frames f3 and f4. However, since the image sensor 1 can receive the light amount dQ2 and the light amount dQ3 by the second photodiode 6, the control amount of the saturation level can be appropriately determined.

[0057] (Second Embodiment)

FIG. 5 is a diagram showing a connection relationship between the circuit configuration of the pixel 53 of the image sensor 51 and the vertical drive circuit 20 that controls the readout timing of the pixel 53 according to the second embodiment of the present invention. Note that the same configurations as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and description thereof is omitted.

In the second embodiment, the amplification factor when amplifying the electrical signal of the first photodiode 5 of the same pixel 53 is changed according to the signal level of the electrical signal of the second photodiode 6. The signal level of the electric signal of the first photodiode 5 is increased so that the signal level of the electric signal of the second photodiode of the same pixel 53 increases. Specifically, it is as follows.

In the image sensor 51 of the second embodiment, instead of the amplifier transistor 13 of the image sensor 1 of the first embodiment, an amplifier transistor (amplifier element) 63 configured by a variable gain amplifier is arranged. Yes. The connection of the drain, source, and gate of the amplifier transistor 63 is the same as in the first embodiment. In the amplifier transistor 63, for example, the larger the signal level applied to the control gate, the higher the amplification factor. The control gate has a second transfer transistor. Connected to the drain of Star 25!

[0060] Between the control gate of the amplifier transistor 63 and the drain of the second transfer transistor 25, the storage node SN2 is also switched to the connection state to the power supply line 27, and the power supply voltage VAA2 is applied to the storage node SN2. A reset transistor 26 is provided for charging and resetting the accumulated charge. The reset transistor 26 has a drain connected to the power supply line 27, a source connected to the storage node SN2, and a gate connected to a control line 28 that controls voltage application. Note that a voltage is applied to the control line 28 by the vertical drive circuit 20 as in the case of the first control line 15.

The operation of the image sensor 51 according to the second embodiment will be described.

[0062] In the pixel 53 of the image sensor 51, similarly to the first embodiment, the reset transistor 11 is turned on and the power supply voltage VAA is applied to the storage node SN, thereby being stored in the storage node SN. The charges are discharged and each pixel is reset. Further, in synchronization with this, the reset transistor 26 is turned on and the power supply voltage VAA2 is applied to the storage node SN2, whereby the charge accumulated in the storage node SN2 is discharged.

[0063] Photoelectric conversion is performed in the first photodiode 5 and the second photodiode 6 with the first transfer transistor 12 and the second transfer transistor 25 turned off, and the first photodiode 5 and the second photodiode 6 Charge is accumulated.

[0064] When a voltage is applied to the second control line 16, the first transfer transistor 12 and the second transfer transistor 25 are simultaneously turned on. An electric signal based on the electric charge accumulated in the first photodiode 5 is input to the gate of the amplifier transistor 63 via the storage node SN and amplified. At this time, an electric signal based on the electric charge accumulated in the second photodiode 6 is input to the control gate of the amplifier transistor 63, and the gain changes as the signal level of the electric signal increases. To do.

Therefore, the signal level of the electrical signal based on the charge generated in the first photodiode 5 is increased as the signal level of the electrical signal based on the charge generated in the second photodiode 6 of the same pixel is higher. Will be increased to be larger.

[0066] According to the second embodiment described above, the same effect as in the first embodiment can be obtained. Further, as the signal level of the electric signal of the second photodiode 6 is increased, the first pixel 53 of the same pixel 53 is increased. Since the amplification factor when the electric signal of the photodiode 5 is amplified is increased, the signal can be corrected when the electric signal of the first photodiode 5 is amplified, and the configuration is simple.

[0067] (Third embodiment)

FIG. 6 is a diagram illustrating a connection relationship between the circuit configuration of the pixel 103 of the image sensor 101 according to the third embodiment of the present invention and the vertical drive circuit 20 that controls the readout timing of the pixel 103. Note that the same configurations as those of the first and second embodiments are denoted by the same reference numerals as those of the first and second embodiments, and description thereof is omitted.

In the third embodiment, in addition to the configuration similar to that of the second embodiment, a voltage control circuit (increase control unit, signal level conversion) is connected between the storage node SN2 and the control gate of the amplifier transistor 63. Part) 30 is provided. The voltage control circuit 30 may be provided for each pixel, or one (for example, one for each vertical signal line 14) may be provided for a plurality of pixels. One may be provided. The operation of the image sensor 101 of the third embodiment is the same as that of the second embodiment except for the operation of the voltage control circuit 30.

[0069] Voltage control circuit 30 converts the signal level (voltage) of the electrical signal input from storage node SN2 and outputs it. For example, the voltage control circuit 30 performs various calculations based on the electrical signal of the second photodiode 6 so as to be amplified while being corrected more preferably than the electrical signal strength of the first photodiode 5! !ヽ Outputs an electric signal with a signal level corresponding to the calculation result.

For example, in FIG. 2, in order to simplify the explanation, a case where the light intensity force that is not reflected in the electric signal by the first photodiode 5 is directly converted into an electric signal by the second photodiode 6. Illustrated. That is, the saturation level indicated by the solid line L2 and the level of the amount of light absorbed by the first photodiode 5 and the substrate 2 indicated by the solid line L4 are approximately the same, and the range of xl to x2 and the range of χΐ to χ2 ' Is about the same.

However, the photoelectric conversion rate and transmittance of the first photodiode 5, the photoelectric conversion rate of the second photodiode 6, and the distance between the first photodiode 5 and the second photodiode 6 so as to satisfy such a relationship. It is troublesome to set the transmittance of the substrate 2 interposed between the two.

[0072] Therefore, these settings are set appropriately. Instead, the amount of light actually incident on the first main surface S1 and the signal of the electric signal output from the first photodiode 6 are determined by experiments or the like. The correlation between the level and the signal level of the electrical signal output from the second photodiode 6 is specified, and the electrical signal at the saturation level of the first photodiode 5 is suitably amplified based on the correlation. Data indicating the relationship between the signal level of the output signal of the second photodiode 6 and the amplification factor is created and stored in the voltage control circuit 30. When the voltage control circuit 30 applies a voltage corresponding to the output signal of the second photodiode 6 to the gate voltage of the amplifier transistor 63 based on the data, the electric signal of the first photodiode 5 is preferably amplified. The

It should be noted that the output signal of the second photodiode 6 is output from the amplifier transistor 63 with respect to the timing at which the output signal of the first photodiode 5 is output to the amplifier transistor 63 by performing an operation or the like in the voltage control circuit 30. If there is a delay in the timing output to the control gate, the output signal of the first photodiode 5 should be synchronized by an appropriate method such as buffering!

[0074] According to the third embodiment described above, it is possible to amplify the signal of the first photodiode 5 with a more favorable amplification factor than in the second embodiment.

[0075] (Fourth embodiment)

FIG. 7 is a diagram showing a connection relationship between the circuit configuration of the pixel 203 of the image sensor 201 according to the fourth embodiment of the present invention and the vertical drive circuit 20 that controls the readout timing of the pixel 203. In addition, about the structure similar to 1st-3rd embodiment, the same code | symbol as 1st-3rd embodiment is attached | subjected and description is abbreviate | omitted.

In the fourth embodiment, the circuit configuration related to the first photodiode 5 (upper side in the drawing) and the circuit configuration related to the second photodiode 6 (lower side in the drawing) are configured similarly. The ON / OFF timing of the reset transistor 11 and the transfer transistor 12 related to the first photodiode 5 and the ON / OFF timing of the reset transistor 211 and the transfer transistor 212 related to the second photodiode 6 of the same pixel are the operation control circuit 223. Is synchronized.

[0077] Then, the output signal of the horizontal driving circuit power corresponding to the first photodiode 5 and the output signal of the horizontal driving circuit power corresponding to the second photodiode 6 are added by the adding unit 230. The signal level of the electric signal of the first photodiode 5 increases according to the signal level of the electric signal of the second photodiode 6. Note that the adder 230 is the third embodiment. Like the voltage control unit 30 in the state, the electric signal from the second photodiode 6 may be appropriately corrected and the force may be added to the electric signal of the first photodiode 5.

According to the fourth embodiment described above, the circuit configuration related to the second photodiode 6 can be made the same as the conventional circuit configuration, and the manufacturing process is almost the same as the first photodiode 5. Manufacturing costs can be reduced.

[0079] (Fifth embodiment)

FIG. 8 is a cross-sectional view schematically showing an image sensor 301 according to the fifth embodiment of the present invention. In addition, about the structure similar to 1st-4th embodiment, the same code | symbol as 1st-4th embodiment is attached | subjected and description is abbreviate | omitted.

[0080] The imaging device 301 of the fifth embodiment is characterized in that the influence of the dark current of the second photodiode 6 is removed, and the third photodiode 306 for measuring the dark current,

A light-shielding portion 307 that shields the three photodiodes 306;

The third photodiode 306 is, for example, a photodiode having the same configuration as the second photodiode 6, that is, a photodiode having the same material and shape. The third photodiode 306 is arranged on the same plane as the second photodiode 6. I.e.

2 Provided on main surface S2. Further, the configuration for outputting an electrical signal from the third photodiode 306 to the third electrode 310 is the same as the configuration for outputting an electrical signal from the second photodiode 6 to the second electrode 10.

The light shielding portion 307 is formed of a non-translucent material and is disposed on the first main surface S1, and the first main surface S1 side force also blocks the directional light to the third photodiode 306. The light shielding unit 307 is, for example, a metal film such as aluminum. Note that a photodiode for measuring the dark current of the first photodiode 5 may or may not be provided between the third photodiode 306 and the light shielding portion 307.

FIG. 9 is a plan view schematically showing the image sensor 301. FIG. 9A shows the first main surface S1, and FIG. 9B shows the second main surface S2. The third photodiode 306 and the light shielding portion 307 are provided around the arrangement area of the first photodiode 5 and the second photodiode 6. Note that a plurality of signal output terminals 4 for outputting signals output from the horizontal drive circuit 22 to the outside are provided at both ends of the substrate 2. FIG. 10 is a diagram showing a circuit configuration of the image sensor 301. In addition to the circuit configuration similar to that of the first to fourth embodiments described above, the image sensor 301 includes a circuit that corrects the electrical signal of the second photodiode 6 based on the electrical signal output from the third photodiode 306. Have

For example, the imaging element 301 has the same configuration as that of the second embodiment with respect to the first photodiode 5 and the second photodiode 6. Further, the image pickup device 301 includes a transfer transistor 325 and a reset transistor 326 in the same manner as the second photodiode 6 with respect to the third photodiode 306, and the third photodiode 306 has the same length as the second photodiode 6. The electric charge is accumulated in the accumulation time, and an electric signal based on the electric charge is output to the voltage control circuit 330. The voltage control circuit 330 corrects the electric signal from the second photodiode 6 based on the signal level of the electric signal from the third photodiode 306. For example, the signal level force of the electric signal from the second photodiode 6 is also output by subtracting the signal level of the electric signal of the third photodiode 306.

Note that the voltage control circuit 330 stores, for example, the signal level of the electric signal from the third photodiode 306, and at the same time the electric current of the third photodiode 330 at a position close to the second photodiode 6 to be corrected. Read the signal level of the signal and correct the signal level of the electrical signal of the second photodiode based on the read signal level. Use in.

According to the fifth embodiment described above, since the influence of the dark current of the second photodiode 6 can be removed, the first photodiode 5 is based on the signal level distribution of the electric signal of the second photodiode 6. When the signal level distribution of the electrical signal is corrected, it can be more accurately approximated to the actual light quantity distribution.

[0088] (Sixth embodiment)

FIG. 11A is a cross-sectional view schematically illustrating an image sensor 401 according to the sixth embodiment of the present invention, and FIG. 11B is a plan view of the image sensor 401 also viewed from the subject side force. In addition, about the structure similar to 1st-5th embodiment, the same code | symbol as 1st-5th embodiment is attached | subjected and description is abbreviate | omitted.

The image sensor 401 includes a second substrate 402 that is disposed to face the second main surface S2 of the substrate 2. The second photodiodes 6 are arranged on the third main surface S3 of the second substrate 402 facing the second main surface S2 of the substrate 2. The second photodiode 6 is provided immediately below the first photodiode 5 as in the first embodiment.

[0090] The substrate 2 and the second substrate 402 are joined by an appropriate joining means such as a solder ball or an insulating adhesive. The substrate 2 may be thinned to about 100 microns by polishing, for example, to increase the light incident property on the second substrate 402. The electrical signal of the first photodiode 5 is output from, for example, a signal output terminal 404 formed at the end of the substrate 2 and is connected to the second substrate 402 via a wire 431 formed by metal wire bonding such as Au or A1. The signal is input to the signal input terminal 432 formed in

[0091] The second substrate 402 is formed wider than the substrate 2, and a signal processing unit 435 is formed outside the arrangement region of the substrate 2 on the third main surface S3 of the second substrate 402. . The signal processing unit 435 executes processing of electrical signals from the first photodiode 5 and the second photodiode 6, and the processed signal is formed on the end of the third main surface S3 of the second substrate 402. Output from external output terminal 437.

The circuit configuration of the pixels of the image sensor 401 is the same as that of the fourth embodiment shown in FIG. 7, for example. The circuit related to the first photodiode 5 (upper side of the drawing in FIG. 7) is provided on the substrate 2, and the circuit related to the second photodiode 6 (lower side of the drawing in FIG. 7) is provided on the second substrate 402. The operation control circuit 223 and the adding unit 230 are provided on the second substrate 402, for example, and the adding unit 230 is included in the signal processing unit 435. By adding the adding unit 230 to the signal processing unit 435, at least a part of the increasing unit is provided on the second substrate 402.

Further, in the circuit configuration of the pixel of the image sensor 401, for example, instead of the adding unit 230 in FIG. 7, an amplifier transistor 63 configured by the voltage control circuit 30 and the variable gain amplifier shown in FIG. The voltage control circuit 30 and the amplifier transistor 63 may be formed in the signal processing unit 435. In this case, since the voltage control circuit 30 is included in the signal processing unit 435, at least a part of the increase control unit that controls the operation of the increase unit is provided on the second substrate 402.

According to the sixth embodiment described above, the processing becomes easier as compared with the case where the first photodiode 5 and the second photodiode 6 are provided on the front and back of one substrate. Per board Since a process for providing a photodiode or the like on one main surface is performed, the conventional manufacturing process can be used as it is, and the alignment of the first photodiode 5 and the second photodiode 6 is performed on the substrate 2 and the second substrate 402. It is also possible to do it by alignment.

Further, the power that can provide the addition unit 230, the amplifier transistor 63, and the voltage control circuit 30 on the second substrate 402, that is, an increase control unit that controls at least a part of the increase unit and the operation of the increase unit. Since at least a part of the second substrate 402 can be provided on the second substrate 402, the degree of freedom in design is improved.

[0096] (Seventh embodiment)

FIG. 12 is a block diagram showing the basic configuration of the camera module 501 of the seventh embodiment. The camera module 501 is used for an appropriate application such as an in-vehicle camera or a mobile phone camera, and includes the imaging devices 1, 51, 101, 201, 301, 401 of the first to sixth embodiments. Yes (The image sensor 1 is shown below as a representative.) O

[0097] The camera module 501 includes an imaging unit 503 including an imaging device 1 and an optical unit 502 including a lens group, an AZD conversion unit 504 that converts a signal from the imaging device 1 into a digital signal, and a post-A / D conversion A video signal processing unit 505 that performs various processing on the digital signal, an image memory 507 that stores video signals in units of one frame or one field for video signal processing, a register that stores various parameters necessary for video signal processing 508 and a control unit 506 for controlling other units.

The video signal processing unit 505 performs various processes such as white balance adjustment, interpolation processing, and γ processing, and outputs the processed image as an RGB or YUV image signal. Or, when the camera module 501 is configured for in-vehicle use, the video signal processing unit 505 detects a white line on the road or detects an obstacle based on a signal from the imaging unit 503.

[0099] Part or all of the signal processing and control described as being executed in the imaging device in the first to sixth embodiments is shared by the control unit 506 and the video signal processing unit 505 of the camera module 501. It is possible to make it.

[0100] (Eighth embodiment)

FIG. 13 is a block diagram showing a basic configuration of a camera module 601 of the eighth embodiment. Note that the same components as those in the seventh embodiment are denoted by the same reference numerals and description thereof is omitted. The image sensor 602 of the camera module 601 is configured in substantially the same manner as the image sensor 201 shown in FIG. 7, for example. However, the image sensor 602 is not provided with the addition unit 230, and the video signal processing unit 605 functions as the addition unit 230 in FIG. That is, the electrical signal of the first photodiode 5 and the electrical signal of the second photodiode 6 are separately output to the AZD conversion unit 604 and AZD converted, and output to the video signal processing unit 605. Then, the video signal processing unit 605 adds the digital signal based on the charge generated in the first photodiode 5 and the digital signal based on the charge generated in the second photodiode 6 to perform the first processing. 1 Increase the signal level of the electrical signal generated by the photodiode 5 in accordance with the signal level of the electrical signal generated by the second photodiode 6.

Note that in the eighth embodiment, the force video signal processing unit 605 described as increasing the signal output from the image sensor 602 by the video signal processing unit 605 provided outside the image sensor 602 is used. It can be understood as an increasing part of the image sensor of the present invention, in other words, an image sensor can be defined including the video signal processing unit 605.

[0103] (Ninth Embodiment)

FIG. 14 is a cross-sectional view schematically showing an image sensor 701 according to the ninth embodiment of the present invention. In addition, about the structure similar to 1st-8th embodiment, the same code | symbol as 1st-8th embodiment is attached | subjected and description is abbreviate | omitted.

In the image pickup device 701 of the ninth embodiment, the first photodiode 5 is provided on the first main surface S1 of the substrate 2, and the second photodiode 6 is provided on the second main surface S2 of the substrate 2. This is the same configuration as the first embodiment. However, the ninth embodiment is different from the first embodiment in that the second photodiode 6 is arranged so as to be shifted to the outer peripheral side with respect to the first photodiode 5 in the pixel 3 on the outer peripheral side of the pixel arrangement region. Form and configuration are different. The pixel arrangement area is an area where all the pixels 3 are arranged.

In general, the image sensor is arranged so that the center of the pixel arrangement region and the optical axis of the lens and Z or the center of the stop are substantially coincident. Therefore, the incident light that passes through the lens and Z or the aperture and enters the imaging device is incident on the first principal surface S1 almost perpendicularly at the center of the pixel array area as indicated by the arrow yl. On the outer periphery side of the area, The light is incident obliquely at an incident angle Θ 1 from the center to the outer periphery.

Therefore, by arranging the second photodiode 6 so as to be shifted to the outer peripheral side of the pixel array region with respect to the first photodiode 5 as the pixel 3 on the outer peripheral side of the pixel array region, in other words, The second photodiode 6 is shifted from the first photodiode 5 in the direction away from the optical axis of the lens and Z or the central force of the diaphragm, as the pixel 3 is located at a position away from the optical axis of the lens and the central force of the Z or the diaphragm. Therefore, the light that has passed through the first photodiode 5 can be accurately received by the second photodiode 6.

[0107] Preferably, the shift dl between the first photodiode 5 and the second photodiode 6 is dl = tl X tan 0 when the distance between the first photodiode 5 and the second photodiode 6 is tl. Set to be 1. For example, when 0 1 = 15 ° and tl = 50 m, the deviation dl between the first photodiode 5 and the second photodiode 6 is 13. The incident angle θ 1 is, for example, 30 ° at the maximum.

Note that the configuration in which the position of the second photodiode 6 is shifted with respect to the first photodiode 5 as in the ninth embodiment may be applied to the imaging elements of the first to sixth embodiments. In addition, such an image sensor may be applied to the image sensor of the camera module of the seventh and eighth embodiments.

[0109] (Tenth embodiment)

FIG. 15 is a cross-sectional view schematically showing an image sensor 711 according to the tenth embodiment of the present invention. In addition, about the structure similar to 1st-9th embodiment, the same code | symbol as 1st-9th embodiment is attached | subjected and description is abbreviate | omitted.

[0110] The imaging device 711 is the first in that the first photodiode 5 is provided on the first main surface S1 of the substrate 2 and the second photodiode 6 is provided on the second main surface S2 of the substrate 2. The configuration is the same as that of the embodiment. However, the tenth embodiment differs from the first embodiment in that the light receiving area of the second photodiode 6 is wider than the light receiving area of the first photodiode 5. The light receiving area is an area of a surface that receives light incident from the first main surface S1 for photoelectric conversion, and is approximately equal to a projected area of each photodiode on the first main surface S1.

[0111] The first photodiode 5 and the second photodiode 6 are arranged, for example, so that their centers substantially coincide. Then, the second photodiode 6 is increased by the larger area of the second photodiode 6. The diode 6 protrudes to the outer peripheral side of the pixel arrangement region with respect to the first photodiode.

[0112] In the tenth embodiment, as in the ninth embodiment, the incident light is incident at an incident angle θ1 and passes through the first photodiode 5, and then enters the non-arranged region of the second photodiode 6. This is suppressed. Furthermore, the light beam imaged in the first photodiode 5 advances while radially spreading after passing through the first photodiode 5, and the cross-sectional area increases. By making the area larger than the light receiving area, the light beam that has passed through the first photodiode 5 can be received without leakage.

Note that, as in the tenth embodiment, the light receiving area of the second photodiode 6 is made larger than the light receiving area of the first photodiode 5, and the second photodiode 6 is connected to the first photodiode 5. Therefore, the configuration that protrudes to the outer peripheral side of the pixel array region may be applied to the imaging elements of the first to sixth and ninth embodiments, and such imaging elements are used in the seventh and eighth embodiments. The power of the camera can be applied to the image sensor of the Mera module.

[0114] (Eleventh embodiment)

FIG. 16 is a cross-sectional view schematically showing an image sensor 721 according to the eleventh embodiment of the present invention. In addition, about the structure similar to 1st-10th embodiment, the same code | symbol as 1st-10th embodiment is attached | subjected and description is abbreviate | omitted.

In the eleventh embodiment, as in the sixth embodiment, the image sensor 721 has a second substrate 402 disposed opposite to the second main surface S2 of the substrate 2, and the second substrate 402 The photodiodes 6 are arranged on the third main surface S3 of the second substrate 402 facing the second main surface S2 of the substrate 2. The circuit configuration is the same as that of the sixth embodiment. However, the eleventh embodiment is different from the sixth embodiment in that the first photodiode 5 is arranged on the second main surface S2 of the substrate 2. The second photodiode 6 is disposed, for example, immediately below the first photodiode 5, and the light receiving areas of the first photodiode 5 and the second photodiode 6 are equal.

[0116] The second main surface S2 and the third main surface S3 face each other with a plurality of spacers 415 interposed therebetween. The spacer 415 is, for example, a solder bump, and keeps the second main surface S2 and the third main surface S3 at a predetermined interval. The distance between the second main surface S2 and the third main surface S3 is, for example, 10 m or less.

[0117] According to the eleventh embodiment, the distance between the second main surface S2 and the third main surface S3 is reduced. Therefore, it is possible to suppress the light that has entered the first main surface SI at the incident angle θ 1 and has passed through the first photodiode 5 from being shifted from the second photodiode 6.

[0118] Since the light received by the first photodiode 5 has passed through the substrate 2 made mainly of silicon, the visible light is cut off, and the light in the infrared region occupies most of the light. For this reason, the image sensor 721 can be suitably used for an infrared camera, an infrared sensor, or the like.

Note that the image sensor 721 of the eleventh embodiment may be applied to the image sensor of the camera module of the seventh and eighth embodiments. In the image sensor 721 of the eleventh embodiment, The position of the second photodiode 6 is shifted from the first photodiode 5 as in the ninth embodiment, or the light receiving area of the second photodiode 6 as in the tenth embodiment. To make the light receiving area of the fifth photodiode 5 larger, it is a matter of course.

[0120] The present invention is not limited to the above embodiment, and may be implemented in various modes.

[0121] The image sensor may be an XY address type such as a MOS type or a charge transfer type such as a CCD. In the case of the XY address system, the embodiment discloses a so-called amplification type imaging device in which an amplifying device is provided for each pixel. However, amplification is performed for all pixels of the imaging device or a part of a plurality of pixels. One element may be provided. Combine the configurations of the first to eighth embodiments as appropriate.

[0122] For example, in the fourth embodiment shown in FIG. 7, the amplifier transistors 13 and 213 are omitted, and the voltage control circuit 30 and the third embodiment shown in FIG. A pair of amplifier transistors 63 composed of variable gain amplifiers may be provided. In this case, the amplification factor of the electric signal of the first light receiving element can be controlled for each pixel based on the electric signal of the second light receiving element by one variable gain amplifier provided for all the pixels of the image pickup element.

Further, for example, in the first embodiment shown in FIG. 3, the voltage control circuit 30 (signal level control in the third embodiment shown in FIG. 6 is interposed between the transfer transistor 25 and the storage node SN. Circuit) and correct the signal level of the electrical signal from the second photodiode 6 so that it more closely approximates the signal level of the electrical signal corresponding to the amount of light that has been photoelectrically converted by the first photodiode 5. Thereafter, addition may be performed. To approximate As described in the third embodiment, the amount of voltage conversion in the voltage control circuit 30 is determined by the amount of incident light on the first main surface S1 and the signal level of the electrical signal of the first photodiode 5 by experiments or the like. It may be determined by specifying the correlation with the signal level of the electrical signal of the second photodiode 6.

Further, for example, in the tenth embodiment shown in FIG. 15, the second photodiode 6 having a light receiving area larger than that of the first photodiode 5 is changed as in the ninth embodiment shown in FIG. One photodiode 5 may be shifted from the outer peripheral side of the pixel array region. The amount of deviation in this case may be set so that, for example, dl = t x tan 0 1 as in the ninth embodiment.

[0125] The first light receiving element only needs to be able to receive light incident on one main surface (first main surface S1 in the embodiment) of the substrate. Therefore, it may be disposed on the first main surface S1 as in the first embodiment, or may be disposed on the second main surface S2 as the other main surface as in the eleventh embodiment. It may be embedded in the substrate.

[0126] The second light receiving element is positioned at the back side of the first light receiving element, that is, at a position where it can receive light that is incident on one main surface of the substrate and passes through at least one of the first light receiving element and the substrate. Anything provided is acceptable. If the incident light energy is absorbed by at least part of the first light receiving element or at least part of the substrate, the amount of light received by the second light receiving element is less than the amount of light received by the first light receiving element. Even if the saturation level is exceeded, the light quantity distribution can be specified in the second light receiving element. Therefore, for example, the second light receiving element may be embedded in the substrate. When the second light receiving element is embedded in the substrate, it may be embedded in the substrate on which the first light receiving element is provided, or another substrate (for example, the second substrate 402 in the embodiment). / That's okay.

[0127] When the second light receiving element is provided on the second substrate (second substrate 402 in the embodiment), the distance between the substrate on which the first light receiving element is provided (substrate 2 in the embodiment) and the second substrate is It may be set appropriately. If the insulation between the first light receiving element and the second light receiving element is ensured, the substrate on which the first light receiving element is provided and the second substrate may be in contact with each other. For example, in the sixth embodiment, the substrate 2 and the second substrate 402 may be in contact with each other.

[0128] The shape and size of the first light receiving element and the shape and size of the second light receiving element are different from each other. May be. For example, in the tenth embodiment shown in FIG. 15, the case where the light receiving area of the second photodiode 6 as the second light receiving element is larger than the light receiving area of the first photodiode 5 as the first light receiving element is illustrated. However, the light receiving area of the second light receiving element may be smaller than the light receiving area of the first light receiving element. If the shape and size of the first light receiving element are different from the shape and size of the second light receiving element, the second light receiving element has a pixel relative to the first light receiving element as in the ninth embodiment shown in FIG. For example, whether the center of the light receiving surface of the second light receiving element is shifted to the outer peripheral side of the pixel array region with respect to the center of the light receiving surface of the first light receiving element is determined as to whether or not it is shifted to the outer peripheral side of the array region. It can be specified by whether or not the power is.

[0129] The saturation level control unit that controls the saturation level of the first light receiving element may control the saturation level based on at least one of the electric signal of the first light receiving element and the electric signal of the second light receiving element. Therefore, the present invention is not limited to the one that controls the saturation level based on both the electric signal of the first light receiving element and the electric signal of the second light receiving element as described in the first embodiment. As in the past, the saturation level may be controlled based only on the electrical signal of the first light receiving element! /, And the saturation level may be controlled based only on the electrical signal of the second light receiving element. Also good. However, if the saturation level is controlled based on the electrical signal of the second light receiving element, the difference between the incident light amount and the saturation level is smaller than when the saturation level is controlled only based on the electrical signal of the first light receiving element. This makes it easier to identify and to make the saturation level follow the amount of incident light.

[0130] Further, the saturation level control unit is a pixel that saturates as long as it controls the saturation level of the first light receiving element so that the degree of charge saturation in the first light receiving element is within a predetermined range. However, the present invention is not limited to the one that controls the saturation level so that is completely eliminated. For example, it is possible to control so that saturated pixels become a predetermined number.

Claims

The scope of the claims

[1] a substrate;

A light receiving element provided for each pixel obtained by dividing the substrate into a plurality of pixels. The light receiving element is provided on the substrate, receives light incident on one main surface of the substrate, and generates a charge corresponding to the amount of light received.

1 light receiving element,

A light receiving element provided for each pixel, the light receiving element provided at a position behind the first light receiving element, incident on the one main surface and transmitted through at least one of the first light receiving element and the substrate; A second light receiving element that receives light and generates a charge corresponding to the amount of light received;

The signal level of the electrical signal based on the charge generated in the first light receiving element is increased so that the amount of increase increases as the signal level of the electrical signal based on the charge generated in the second light receiving element of the same pixel increases. An increasing portion configured to cause

An imaging device comprising:

[2] The first light receiving element is provided on the one main surface,

The second light receiving element is provided on the other main surface of the substrate.

The imaging device according to claim 1.

[3] a second substrate disposed opposite to the other main surface of the substrate;

The second light receiving element is provided on the second substrate.

The imaging device according to claim 1.

[4] The first light receiving element is provided on the one main surface of the substrate,

The second light receiving element is provided on a main surface of the second substrate facing the other main surface of the substrate.

The imaging device according to claim 3.

[5] The first light receiving element is provided on the other main surface of the substrate,

The imaging device according to claim 3.

[6] At least a part of the increase unit and the increase control unit that controls the operation of the increase unit is provided on the second substrate. The imaging device according to claim 3.

[7] The increasing unit adds an electric signal based on the electric charge generated in the second light receiving element of the same pixel to an electric signal based on the electric charge generated in the first light receiving element.

The imaging device according to claim 1.

[8] The increase unit includes an amplification element that amplifies an electric signal based on the electric charge generated in the first light receiving element,

The amplifying element increases the electric signal based on the electric charge generated in the first light receiving element of the same pixel as the signal level of the electric signal based on the electric charge generated in the second light receiving element is larger. Increase amplification factor

The imaging device according to claim 1.

[9] A third light receiving element disposed on the same plane as a surface on which a plurality of the second light receiving elements are arranged, and a light shielding unit that blocks light from the one main surface side toward the third light receiving element. ,

The increasing unit subtracts the signal level of the electric signal based on the electric charge generated in the third light receiving element from the signal level force of the electric signal based on the electric charge generated in the second light receiving element. The signal level of the electrical signal based on the charge generated in step 1 is corrected, and the signal level of the electrical signal based on the charge generated in the first light receiving element is increased based on the corrected signal level.

The imaging device according to claim 1.

[10] Based on at least one of an electric signal based on the electric charge generated in the first light receiving element and an electric signal based on the electric charge generated in the second light receiving element, and thereafter, the electric charge in the first light receiving element. A saturation level control unit configured to control the saturation level of the first light receiving element so that the saturation level of the first light receiving element falls within a predetermined range.

The imaging device according to claim 1.

[11] The pixels on the outer peripheral side of the pixel array region are arranged such that the second light receiving element is shifted to the outer peripheral side of the pixel array region with respect to the first light receiving element of the same pixel.

The imaging device according to claim 1.

[12] The first light receiving element has a light receiving area larger than that of the first light receiving element. To the outer periphery of the pixel array area

The imaging device according to claim 1.

[13] lenses,

An image sensor on which light from the lens forms an image;

A signal processing unit configured to process an electrical signal output from the imaging device, and

The image sensor is

A substrate,

A light receiving element provided for each pixel obtained by dividing the substrate into a plurality of pixels. The light receiving element is provided on the substrate and receives light incident on one main surface of the substrate, and generates a charge corresponding to the amount of light received. When,

A light receiving element provided for each pixel, provided at a position behind the first light receiving element, incident on the one main surface and transmitted through at least one of the first light receiving element and the substrate A second light receiving element that generates a charge corresponding to the amount of light received,

With

The signal processing unit has a high signal level of an electric signal based on the charge generated in the first light receiving element, and a high signal level of the electric signal based on the charge generated in the second light receiving element of the same pixel. It is configured to increase the amount of calories so that the amount of increase increases!

Camera module.

[14] In the pixel at a position where the optical axis force of the lens is also away, the second light receiving element is arranged so as to be shifted in a direction away from the optical axis with respect to the first light receiving element of the same pixel.

The camera module according to claim 13.